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  1. #1

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    Oil Injection pump theory & operation

    I want to fully understand the way this system works.

    I understand that it pumps less oil at idle and more oil at wot, but it is crank driven and is connected via cable to the throttle control.

    Is the increased rpm of the engine that pumps more oil or is it the position of the throttle?

    I'm premixed now but just curious on the way the oil pump works.
    Last edited by K447; 07-17-2015 at 02:43 PM.


  2. #2
    I like pipes. I love boost Mr. GP1800's Avatar
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    Its both actually. Engine RPM and the position of the arm

  3. #3

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    The pressure is made by the engine and the volume is adjusted with the cable as i understand it. We have vacuum pumps on trucks that use the same oil pump but use a screw to adjust the volume instead of a throttle cable.

  4. #4

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    So in theory if the cable snapped, the pressure may still force more oil into the engine than it would at idle as the rpms increase?

  5. #5
    I like pipes. I love boost Mr. GP1800's Avatar
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    Quote Originally Posted by Portcity843 View Post
    So in theory if the cable snapped, the pressure may still force more oil into the engine than it would at idle as the rpms increase?

    If the cable breaks there is a spring on the arm that pulls the pump to full oil.

  6. #6
    This is how I run a jetski shop in the desert nmpeter's Avatar
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    two types of pumps in use:

    constant volume
    volume by throttle


    when a volume by throttle control fails, the pump typically goes to failsafe mode and operates like it was at full throttle ( a little more oil then normal)

    the only real advantage in my view to volume by throttle is that is saves a little injector oil at idle.

  7. #7

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    just covert all to premix, oil pump will save you a little at idle also less smoke at idle. but if it fail then you can kiss your engine goodbye.

  8. #8
    I like pipes. I love boost Mr. GP1800's Avatar
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    IT is very very rare that oil pumps fail. Its almost always the lines that fail on oil injection systems. If you maintain the system, it will be reliable. I love oil injection and I would personally never run premix. People think premix is safer, until you mess up the mixing or someone else fuels the ski for you and doesn't put any oil in it.

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  10. #9

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    Is there a bleeding procedure for the installation of a new pump?

  11. #10
    silver93t's Avatar
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    Yes. Just did this on mine. Might vary for different skis but for my 1300r the factory service manual calls for filling all the lines with oil. Then cracking the bleeder screw 2 full turns. Then cranking until you get a stream of oil with no bubbles. I disconnected the injectors and spark plug wires during the procedure.

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